Jenny Beth Martin, president of Tea Party Patriots, during the 41st annual Conservative Political Action Conference on March 8, 2014 in National Harbor, Maryland.

The Tea Party Patriots flaty predict a win later this month in Mississippi, where favored candidate Chris McDaniel faces 36-year incumbent Sen. Thad Cochran in a run-off for the Republican Party’s nomination.

“Run-offs are about turnout and enthusiasm,” said Kevin Broughton, who runs the Tea Party Patriot Citizens Fund, the group’s super-political action committee. “He was the leading vote-getter in the primary and he’ll be the leading vote-getter in the run-off. State senator McDaniel is going to shock the world.”

The limited-government movement could use a boost. So far, Tea Party groups have seen just one of their preferred Senate candidates win this year as Republicans backed by establishment organizations such as the U.S. Chamber of Commerce have stepped up involvement in primaries.

“It’s politics and elections so we’ll have some losses,” said Jenny Beth Martin, founder and president of the Tea Party Patriots, in an interview today at Bloomberg’s Washington bureau. On the push back from Republican groups, she said: “This is the nature of the beast, we’ve chosen to get into the belly of the beast.”

The Tea Party movement, she said, can point to some victories in the House, including in West Virginia where Alex Mooney, a former Maryland state senator backed by the Tea Party Patriots, is advancing to the November general election.

This is the first election cycle in which the Tea Party Patriots have had a super-PAC. It has collected about $2.6 million this year, according Federal Election Commission records. The group’s average donation is about $40, Broughton said.

Martin says her group’s seven-figure fundraising costs are due to heavy reliance on direct mail, which also serves an educational purpose.

“Our fundraising costs are high compared to what other groups have,” Martin said. “We raise our money from small donors. Small donors aren’t giving millions of dollars.”

Martin foresees a legislative battle over immigration in Washington this year. Her group opposes immigration legislation in Washington, a split for the Tea Party Express — one of the other major Tea Party-aligned organizations, which backs changing the system this year.